The main objective of the proposed International Tuberous Sclerosis Symposium is to raise the current issues in Tuberous Sclerosis Complex (TSC) patient care and research, discuss these issues fully, and to reach a consensus where possible. In some cases, there may be inadequate information to reach a consensus, so that the result will be the identification of future research initiatives to clarify an issue in TSC clinical care and/or research. The result of this meeting could have significant impact on the patient care provided to TSC patients, and on development and funding of research initiatives in TSC. This information will benefit many people. The health care professionals responsible for diagnosing and treating TSC patients will benefit from the results of this meeting. The National Institutes of Health and the National Tuberous Sclerosis Association will benefit from the identification of future research initiatives so that funds can be directed to meaningful, current research issues in TSC. The TSC patients and their families will benefit from new information gained from this meeting, by the education of health care professionals in the clinical care and research issues in TSC, and from consensus recommendations that are reached that can be used to justify diagnostic testing and follow-up screening and clinical treatment. The specific objectives of this symposium are: 1. Review the status of our knowledge regarding the neurobiology of TSC, and the clinical and genetic heterogeneity of TSC, and to determine future directions for both clinical and basic research initiatives; 2. Provide a forum for the discussion of the diagnosis of TSC, including recommendations for tests needed at diagnosis, and suggested optimal, cost-effective follow-up screening and clinical care; 3. Provide a forum for TSC researchers to learn from experts in other research areas related to TSC, and to focus on the aspects that provide insight into the etiology and potential cause(s) of TSC; 4. Evaluate our knowledge regarding behavioral, psychiatric and communication disorders in TSC, and develop protocols for testing, screening and treatment modalities for this population; and 5. Provide a forum for discussion of the status of the genetic research on TSC, and develop a consensus for diagnostic and prenatal genetic testing for TSC.